+/** \brief Create a charcater range converter
+ * \param n the nfa
+ * \param backref_no The backreference to reproduce
+ * \param from_char the first character of the original range
+ * \param to_char the first character of the target range
+ *
+ * This converter takes a backreference, and shifts the characters
+ * by a constant value. For example, translating a-z to A-Z.
+ * Note that backref 0 is always the last character that matched a
+ * range, even if no backrefs were defined in teh nfa. This makes
+ * it pretty useful with this converter.
+ *
+ */
+yaz_nfa_converter *yaz_nfa_create_range_converter (
+ yaz_nfa *n, int backref_no,
+ yaz_nfa_char from_char,
+ yaz_nfa_char to_char);
+